Hawkish GOP Sens. Kelly Ayotte of New Hampshire, Lindsey Graham of South Carolina and John McCain of Arizona are known as the "Three Amigos." (AFP)

WASHINGTON — They brought the typically plodding U.S. Senate to a virtual standstill. They pressured the White House into releasing information that could politically harm the president. They led the first-ever filibuster of a defense secretary nominee. Then, they boldly vowed to continue their struggle.

As recently as last fall, Democratic sources and longtime Washington observers regarded the Amigos — GOP Sens. John McCain of Arizona, Lindsey Graham of South Carolina and Kelly Ayotte of New Hampshire — as an isolated faction that lacked very much political sway within their own caucus.

Their brand of hawkish foreign policy that envisions the widespread use of the U.S. military to advance Washington’s goals and spread democracy across the globe was seen as an outlier in an increasingly isolationist Republican Party. As many Republicans began to sound like Democrats, arguing America’s overseas adventures were too pricey and unwise, the Amigos kept calling for U.S. action in places such as Syria and North Africa.

But as the 112th Congress expired in January, the plates of the political landscape began to shift. By the time the 113th Congress took shape weeks later, a faction once relegated to the GOP’s political periphery had been transported to its epicenter.

On the surface, it appeared the group’s power had lessened. After all, due to term limits, McCain had to give up his seat as Senate Armed Services Committee ranking member. But when ultra-conservative and hawkish Sen. James Inhofe, R-Okla., took over that role, it seems to have given the Amigos a key ally in an influential job. And when Sen. John Cornyn of Texas became the Senate’s No. 2 Republican, it gave the Amigos a direct line into the Senate’s Republican leadership — and by extension, the GOP’s strategy and agenda.

What’s more, McCain appears ready to reclaim his infamous status as the “maverick” of the Senate. He’s feistier lately in public comments and when jousting with reporters, and, notably, increasingly quick to take a swipe at President Barack Obama whenever possible.

Buoyed by their intense collective crusade for answers about how Obama and his administration handled the Sept. 11 attack on U.S. facilities in Benghazi, Libya, the trio led the way as Senate Republicans on Feb. 14 defeated a Democratic motion that would have ended debate on Chuck Hagel’s nomination for defense secretary.

Though the chamber is in recess this week, the Amigos’ filibuster technically is ongoing. Their strategy to use a lengthy debate to both bruise Obama and create additional time to uncover, as Graham put it Feb. 14, a “bombshell” from Hagel’s controversial record that could derail the nomination for good was adopted by Cornyn and Minority Leader Sen. Mitch McConnell, R-Ky.

McCain and Graham sounded conciliatory moments before the filibuster-extending vote. They said they were — for now — satisfied by the White House’s acknowledgement in a reply to the Arizona senator’s letter that Obama did not speak to any U.S. or Libyan official during or immediately after the deadly attack.

Unless their staffs find something damning on Hagel before Feb. 25, the duo said it would vote with Democrats to end debate and allow a Feb. 26 simple-majority vote on the nomination. But Graham made clear the deep-dive into every word Hagel has ever spoken or written will continue during the recess period.

For instance, Graham planted a seed of doubt on his post-recess promises by telling reporters Feb. 14 that he was concerned anew about Hagel’s views. That’s because a Hagel quote had been unearthed in which he insisted the “State Department is an extension of the Jewish lobby,” Graham said, adding he’s “not sure that warrants a bombshell.”

The Amigos’ return has been noticed by the White House.

“I’ve spoken to the vice president this week,” Graham said of Joe Biden. So concerned was the White House that the Amigos might prevent Hagel from becoming defense secretary that Obama deployed not an adviser but his Capitol Hill fix-it man, the former Delaware senator who has known and worked with McCain and Graham for years.

“There’s no doubt about the fact that they used the confirmation to get more information on Benghazi,” said Larry Korb, a former Pentagon official now at the Center for American Progress. “For the White House to write a letter saying this is what the president did and didn’t do, that’s significant. I haven’t seen that before.”

Still, some have questioned the trio’s motivations for pounding Obama so hard over Benghazi and the nomination of Hagel, a Republican who broke with his former friend McCain in 2006 in opposing the Iraq surge.

Once they had extracted from the White House the potentially Obama-damaging Benghazi information, the Amigos said a final vote on the nomination after the 10-day recess was, as McCain said, “appropriate” to allow all members of the Senate ample time to “get further questions answered.”

Some of the trio’s political foes aren’t so sure about that, however.

Asked whether the GOP senators’ tactics were about Washington process or their desire to politically bruise Obama, the No. 2 Senate Democrat, Sen. Richard Durbin of Illinois, had a telling response: “It’s always about the president.”